Well i have a 1994 camaro lt1 6-speed that I recently put headers and exhust on and shortly after my check engine light came on, and it wasnt running like it should... Today I plugged it into my snap-on scanner and i got the code 43 esc module or sensor circuit problem

Thats probably the knock sensor right? and it was running in closed loop could this be the cause of that?

I thought I should use the lt4's because its less resistant to picking up false knock but wasnt sure if it was the actuall sensor down on the block? or just the module in the pcm? and if its the module is it different between obd1 and obd2 pcm?

 

I'm a little confused. Did you switch knock sensors in the block or the knock module in the computer? The knock modules are interchangeable and changing to the LT4 knock module is a typical mod. However the knock sensors are different from OBD1 to OBD2. If you actually changed the sensor, try putting your original back in the block.....

 

DTC 43 is strictly for the knock sensor, or the wire that goes to it. Very easy to check with a multi-meter. Key on, pull the harness connector off, and check for 5V between the pin in the harness connector, and the block. Harness still off the sensor, measure the resistance from the single pin on the sensor and the block. Should be between 3,500 - 4,500 ohms. Put the connector back on the sensor and measure from the pin to the block, should be between 1.5 - 3.5V.

When DTC 43 is active, the PCM retards timing almost all the time, depending on engine operating conditions.

No sure what you are getting at here.... the knock sensor has nothing to do with whether it goes into closed loop. If your coolant is warm, the O2 sensors are hot with no codes, and the timer from startup (~205 seconds) has time out, it should be operating in closed loop.

 

no i didnt change the knock sensor...but this morning I put a knock module from a 1995 t/a in and it still does the same thing so i'm pretty sure the module is fine....

 

There is a separate code (DTC 47) for the knock module.

 

k I'll try that...

 

yep that fixed it when i checked the ohms from the sensor to the block there was nothin so I got a new knock sensor and put it on and no check engine light and it runs a LOT better now thx for the help